This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. In a recent conference sponsored by the NICHD and NIDDK, an alarm was sounded by a group of nationally known investigators that elements of the emerging metabolic syndrome [a constellation of pathologies consisting of obesity, dyslipidemia, hypertension and hyperglycemia] (1) are appearing in increasing frequency in children and adolescents (2). If unchecked, we will witness an unprecedented level of cardiovascular and metabolic disease as this generation becomes adults, and the morbidity and cost will be staggering. While the pathogenic mechanisms of the metabolic syndrome and its elements in children are not fully understood, recent research supports a role for an imbalance between production of reactive oxygen species (ROS) and antioxidant defenses, inducing oxidative stress (3-5). This is compelling because physical activity and nutrition are among the most important naturally occurring modifiers of ROS production and antioxidant defense mechanisms in humans (6-12). In children, key mechanisms governing the interactions among exercise, diet, and the regulation of oxidative stress in the pathogenesis of the metabolic syndrome have yet to be investigated.